It was meant to be an adventure—a night alone on a remote Irish island. Archaeologist Sophie Malone never expected to find Celtic treasure or to end up in a fight for her life in a dark, desolate cave. Now, a year later, she's convinced answers to the mysteries of that night lie in Boston. Is the recent violence there connected to her night of terror? Who has the priceless gold artifacts that disappeared from the cave…and who is responsible for the whispers she heard in the dark?

Nearly killed in an explosion a month ago, Boston detective Cyrus "Scoop" Wisdom has recovered from his injuries. He's after the bomber—and he thinks it's another cop. But when Sophie unknowingly leads him to a retired officer's body amid symbols of ritual sacrifice, it's clear nobody's safe, and everyone's a suspect.

Tough and stubborn, Scoop is the best on the force at detecting lies…except maybe those of Sophie Malone. Together Sophie and Scoop face the greatest challenge of their lives: someone is using ancient rituals to commit modern-day murder—and the killing has only just begun.